A conventional semiconductor device called, for example, a BGA (ball grid array) includes a device in which a semiconductor chip made of, for example, an LSI is mounted in the central portion on the upper surface of a relay substrate (interposer) sized somewhat larger than the semiconductor chip, and connection terminals formed of solder balls are arranged to form a matrix on the lower surface of the relay substrate.
FIG. 45 is a vertical cross sectional view exemplifying the construction of such a conventional semiconductor device. As shown in the figure, a semiconductor chip 1 includes a silicon substrate 2 and a plurality of bump electrodes 3 made of, for example, copper and formed on the lower surface of the silicon substrate 2. A relay substrate 4 is equipped with a base film 5 having a planar size somewhat larger than the planar size of the silicon substrate 2 of the semiconductor chip 1. A plurality of re-wirings 6 electrically connected to the bump electrodes 3 of the semiconductor chip 1 are formed on the upper surface of the base film 5. The re-wirings 6 includes first connection pads 7 arranged to correspond to the bump electrodes 3 of the semiconductor chip 1, second connection pads 8 arranged to form a matrix, and connecting lines 9 serving to electrically connect the first and second connection pads 7 and 8. Further, a circular hole 10 is formed in that portion of the base film 5 which corresponds to the central portion of the second connection pad 8.
The semiconductor chip 1 is bonded to the central portion on the upper surface of the relay substrate 4 with an anisotropic conductive adhesive layer 11 interposed therebetween. The anisotropic conductive adhesive layer 11 includes a thermosetting resin 12 and a large number of conductive particles 13 contained in the thermosetting resin 12.
In mounting the semiconductor chip 1 to the relay substrate 4, the semiconductor chip 1 is simply positioned first in the central portion on the upper surface of the relay substrate 4 with the anisotropic conductive adhesive layer 11 interposed therebetween. Then, a prescribed pressure is applied to the semiconductor chip 1 at the temperature at which the thermosetting resin 12 is cured so as to achieve the bonding between the semiconductor chip 1 and the relay substrate 4. As a result, the bump electrode 3 pushes away the thermosetting resin 12 so as to be electrically connected to the upper surface of the first connection pad 7 with the conductive particles 13 interposed therebetween. In addition, the lower surface of the semiconductor chip 1 is bonded to the upper surface of the relay substrate 4 with the thermosetting resin 12 interposed therebetween.
In the next step, a resin sealing film 14 made of an epoxy resin is formed on the entire upper surface of the relay substrate 4 including the semiconductor chip 1, followed by allowing a solder ball 15 to be connected to the second connection pad 8 within and below the circular hole 10. In this case, a plurality of solder balls 15 are arranged to form a matrix because the second connection pads 8 are arranged to form a matrix. It should be noted that the solder ball 15 has a diameter larger than that of the bump electrode 3 of the semiconductor chip 1. Therefore, in order to avoid the mutual contact of the solder balls 15, it is necessary for the solder balls 15 to be arranged such that the distance between the adjacent solder balls 15 is larger than the distance between the adjacent bump electrodes 3. Such being the situation, where the number of bump electrodes 3 of the semiconductor chip 1 is increased, it is necessary to make the arranging region of the bump electrodes 3 larger than the size of the semiconductor chip 1 in order to obtain the arrangement space required for each of the solder balls 15. Therefore, the size of the relay substrate 4 is made somewhat larger than the size of the semiconductor chip 1. It follows that the solder balls 15 positioned in the peripheral portion of the matrix arrangement of the solder balls 15 are arranged in the periphery of the semiconductor chip 1.
As described above, in the conventional semiconductor device in which the connection terminals formed of the solder balls 15 are also arranged in the periphery of the semiconductor chip 1, the lower surfaces of the bump electrodes 3 of the semiconductor chip 1 are electrically connected by the bonding method using the relay substrate 4 having the re-wirings 6 formed thereon to the upper surfaces of the first connection electrodes 7 of the re-wirings 6 of the relay substrate 4 with the conductive particles 13 contained in the anisotropic conductive adhesive layer 11 interposed therebetween. The particular construction gives rise to the problem that it is possible for the defective connection to take place depending on the state of the bonding. Also, it is necessary to mount the semiconductor chips 1 one by one to the relay substrate 4 so as to make the manufacturing process troublesome. The particular situation also takes place in the case of a semiconductor device of a multi-chip module type comprising a plurality of semiconductor chips. Particularly, in the case of a multi-chip module type semiconductor device, the semiconductor device is provided in many cases with chip parts such as a capacitor, an inductor and a resistor in addition to the plural semiconductor chips. What should be noted is that the bonding process is rendered more complex if the shapes and thicknesses of the semiconductor chips and the chip parts differ from each other.